Coal liquefaction process

ABSTRACT

1. A PROCESS FOR THE LIQUEFACTION OF COAL WHICH COMPRISES CONTACTING THE COAL, AT A TEMPERATURE OF FROM ABOUT 150:C TO ABOUT 375*C AND A PRESSURE OF FROM ABOUT 10 TO ABOUT 300 ATMOSPHERES FOR A CONTACT TIME CORRESPONDING TO FORM 1 TO 600 MINUTES OR A LIQUID HOURLY SPACED VELOCITY OF ABOUT 0.16 TO ABOUT 1.0, WITH FROM ABOUT 100 WT. PERCENT TO ABOUT 1,000 WT. PERCENT OF WATER, A REDUCTING GAS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN CARBON MONOXIDE AND MIXTURES THEREOF IN AN AMOUNT OF FROM ABOUT 0.5 TO ABOUT 175 SCF. PER POUND OF CARBON IN THE COAL, AND FROM ABOUT 0.01 WT. PERCENT TO ABOUT 1,000 WT. PERCENT OF A CATALYST CONSISTING ESSENTIALLY OF A CATALYTIC SULFUR COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL AND AMMONIUM SULFIDES, SULFITES AND THIOSULFATES.

United States Patent 3,846,275 COAL LIQUEFACTION PROCESS Peter Urban,Northbrook, BL, assignor to Universal Oil Products Company, Des Plaines,Ill. No Drawing. Filed Sept. 15, 1972, Ser. No. 289,502 Int. Cl. (110g1/06 U.S. Cl. 208- 13 Claims ABSTRACT OF THE DISCLOSURE A process isdisclosed for de-ashing and liqucfying coal which comprises contactingcomminuted coal with water, a reducing gas, and a compound containing asulfur component and an alkali metal ion or ammonium ion component, atelevated temperatures and pressures.

BACKGROUND This invention relates to a process for convertingcarbonaceous solids to more valuable hydrocarbonaceous products. Morespecifically, this invention relates to a process for de-ashing andconverting coal to hydrocarbon products by contacting the coal withWater, a compound containing sulfur and an alkali metal ion or ammoniumion, and a reducing gas, at particular liquefaction conditions toprovide the hydrocarbon products.

Several methods for converting coal to more valuable liquid orliquefiable products are known to the art. One method employsdestructive distillation of the coal. More recently, high pressurehydrogenation and solvent extraction techniques have been employed. Oneof the more onerous difficulties encountered in prior coal liquefactionart is the separation of the liquefied hydrocarbonaceous products fromthe unconverted coal, ash, and various solid inorganic materials foundin the raw coal. Under typical prior art liquefaction conditions, thesolids are dispersed in the liquefied material and in the organicsolvent, if one is used, in a finely divided particulate state,rendering separation extremely difficult. Settling, centrifuging andfiltration techniques have been employed with some success, but areeconomically unattractive as a means for de-ashing the liquefiedmaterials.

The hydrocarbonaceous product of coal liquefaction typically requiresfurther treatment by techniques analogous to petroleum refining methodsin order to convert the liquefaction product into valuable liquidhydrocarbons such as gasoline, or to provide benzene and other organicchemicals. This further treatment generally comprises catalytichydrogenation and cracking of the hydrocarbonaceous tars that resultfrom liquefaction. It has been found that, in general, the particulatematter must be removed from the liquefaction product before such furthertreatment can effectively and economically be undertaken. Consequently,the prior art has concentrated on methods for economically separatingash from the liquefaction product. The process of this inventionpartially obviates the need for such separation techniques, by reducingthe ash content of the liquefaction product to a low level. Further, thelesser amount of ash which does remain is hydrophilic, and can beremoved from the liquefaction product by simple Water washing anddecantation, in contrast to the non-hydrophilic ash in prior art coalliquefaction processes, which is not susceptible to removal by waterWashing.

Another major drawback of prior art coal liquefaction methods has beenthe requirement for large amounts of hydrogen both in high pressurehydrogenation and in solvent extraction. It has been suggested that thisproblem can be overcome by converting only that small fraction of thecoal which is relatively rich in hydrogen. It is obviously moredesirable to convert as large a fraction 3,846,275 Patented Nov. 5, 1974as possible of the coal to valuable products. A process which couldemploy a low cost substitute for hydrogen, or substantially reduce theamount of hydrogen needed, would be economically more attractive thanprior art methods and Would constitute a significant advancement.

SUMMARY An object of the present invention is to provide a novel processfor the liquefaction of carbonaceous solids to produce more valuablehydrocarbonaceous products.

A further object of the present invention is to provide an improvedprocess for liquefying coal, utilizing liquid phase Water and a readilyavailable reducing gas, to produce valuable hydrocarbonaceous products.

A particular object of the present invention is to provide a process forliquefying coal in which the ash content of the product is reduced,resulting in a hydrocarbonaceous product of greater utility, while ashremaining in the product is hydrophilic.

In one embodiment, the present invention relates to a process forconverting a solid carbonaceous material to a hydrocarbonaceousliquefaction product which comprises contacting said solid material witha reducing gas, water, and a catalytic compound containing a sulfurcomponent and an alkali metal ion or ammonium ion component, atliquefaction conditions, and recovering said hydrocarbonaceous productfrom the resulting mixture.

In another, more limited embodiment, the present invention relates to aprocess for converting a solid carbonaceous material to ahydrocarbonaceous liquefaction product which comprises: contacting thesolid material with a reducing gas, water, and a catalytic compoundcontaining a sulfur component and an alkali metal ion or ammonium ioncomponent at liquefaction conditions; separating the resulting mixtureinto an aqueous phase and a hydrocarbonaceous phase; extracting thehydrocarbonaceous phase with a hydrocarbonaceous solvent to provide anextract fraction and a solid residual fraction; and recovering theliquefaction product from the extract fraction.

I have discovered that coal and other carbonaceous solid materials canbe liquefied to produce valuable hydrocarbonaceous products by treatingthe coal with a relatively large quantity of water, a reducing gas, anda compound containing a sulfur component and an alkali metal ion orammonium ion component. I have found that the ash content of the coalcan thereby be reduced significantly and that the hydrocarbonaceousproduct may, in some cases, be further processed catalytically, in amanner analogous to petroleum refining methods, without the necessity ofremoving further ash and undissolved carbonaceous materials from theliquefaction product. The ash which does remain in the liquefactionproduct, being hydrophilic, can be removed by simple water washing, thusobviating the problem of ash removal encountered in prior art. In placeof relatively expensive hydrogen, employed in prior art liquefactionmethods, carbon monoxide, or a mixture of carbon monoxide with hydrogenprovides an effective reducing gas in the present process, permittingthe use of low cost sources of reducing gas, e.g. synthesis gas.

PREFERRED EMBODIMENT The carbonaceous solid materials which can beutilized in the present process to provide the hydrocarbonaceous productinclude any sort of coal, lignite, peat, oil shale, tar sand or similarsubstance. The preferred carbonaceous solid is a bituminous coal. Forexample, an Illinois Bellville District Stoker Coal having a moistureand ash free volatile content of about 20% or higher is suitable.Although not essential to the process, it is preferred that thecarbonaceous solid to be employed in the process is first reduced to aparticulate, comminuted form. Preferably, the carbonaceous solid isground or pulverized to provide particles sufficiently small to passthrough a 100 mesh Tyler sieve or smaller. Coal ground sufficiently topass through a 200 mesh sieve is particularly preferred.

The applicable sulfur-containing and alkali metal ioncontaining orammonium ion-containing catalytic compounds are those capable of beingcatalytically reduced at the liquefaction conditions hereinafterdescribed. These include, for example, alkali metal sulfides, alkalimetal sulfites, alkali metal thiosulfates, ammonium sulfide, ammoniumsulfite, ammonium thiosulfate, etc. Particular compounds which arepreferred for use as the sulfurcontaining catalytic compound in thepresent process include sodium sulfide, potassium sulfide, sodiumsulfite, potassium sulfite, sodium thiosulfate, potassium thiosulfate,sodium hydrosulfide, potassium hydrosulfide, sodium hydrogen sulfite,potassium hydrogen sulfite, sodium pyrosulfite, potassium pyrosulfite,the disulfides, trisulfides, tetrasulfides, and pentasulfides of sodiumand potassium. Also preferred are the analogous ammonium compoundsincluding ammonium sulfide, ammonium hydrosulfide, ammonium sulfite,ammonium hydrogen sulfite and ammonium thiosulfate. Other suitablecompounds include lithium sulfide, lithium hydrosulfide, lithiumsulfite, rubidium sulfide, cesium sulfides, etc.; however, sodium andpotassium are particularly preferred alkali metals. Othersulfur-containing and alkali metal ionor ammonium ion-containingcompounds may be employed but not necessarily with equivalent results.

The reducing gas employed in the present process may be pure hydrogen orpure carbon monoxide. A mixture of these gases is also suitable. Thereducing gas may be commingled with one or more gases or vapors whichare relatively inert in the liquefaction reaction, including nitrogen,carbon dioxide, etc. One convenient, suitable source of the reducing gasis a synthesis gas produced by reaction of carbon or hydrocarbons withsteam to produce carbon monoxide and hydrogen. A variety of methods forproducing a synthesis gas suitable for use in the present process areknown in the art.

Liquefaction conditions in the process of the present invention includea broad temperature range of about 150 C. to about 375 C. and a pressureof about atmospheres to about 400 atmospheres or more. Preferredconditions include a temperature of about 200 C. to about 375 C. and apressure of about 10 atmospheres to about 300 atmospheres. I have foundthat excellent results are obtained when at least a portion of the wateremployed in the liquefaction operation is maintained in the liquid phaseby appropriate adjustment of the temperature and pressure employed inthe operation. Thus, preferred liquefaction conditions include atemperature of about 200 C. to about 375 C. and a pressure at leastsufficient to provide a liquid water phase at the desired temperature.For example, in an operation wherein it is desired to employ atemperature of about 200 C., a pressure of at least about atmospheres ismaintained. At higher temperature operations, e.g., 350-375 C., apressure of about 135 amtospheres to about 220 atmospheres or more ismaintained. \Best results are achieved when a temperature of about 250C. to about 350 C. is employed. Liquefaction conditions can also includethe use of a hydrocarbonaceous solvent in the liquefaction operation, ifdesired. In general, better results are achieved when a solvent isemployed. When such a solvent is utilized, it is provided at aconcentration of about 1.0 wt. percent to about 1,000 wt. percent of thesolid carbonaceous material. Particular hydrocarbonaeous solventsutilized in coal liquefaction are well known to the art. Among thesolvents preferred in the present process are benzene, toluene, xylenes,ethylbenzene, and similar aromatic and alkylaromatic hydrocarbons.

The amount of water contacted with the solid carbonaceous material atliquefaction conditions is between about wt. percent and about 1,000 wt.percent of the carbonaceous solid. Good results are obtained when theamount of water is between about 100 wt. percent and about 400 wt.percent of the carbonaceous solid. The amount of the sulfur-containingand alkali metalcontaining or ammonium ion-containing compound contactedwith the solid is sufiicient to provide a concentration of about 0.01wt. percent to about 1,000 wt. percent of the carbonaceous solid. Aconcentration of about 0.1 wt. percent to about 200 wt. percent based onthe carbonaceous solid, is preferred. The sulfurcontaining compound mayconveniently be employed as an aqueous solution of, for example, sodiumsulfite, etc., in the water component. When this method is employed, itis preferred to maintain a concentration of about 10 wt. percent or moreof the sulfur-containing compound in solution. The superatmosphericpressures employed at liquefaction conditions in the present process maybe wholly supplied by the reducing gas, or may be supplied in part, byinert gases, water vapor, etc. In any case, the partial pressure of thereducing gas is maintained as at least about 10% of the total pressure.The amount of the reducing gas employed is about 0.5 s.c.f. to abouts.c.f. per pound of carbon in the carbonaceous solid to be processed.Preferably, the amount of the reducing gas utilized is about 20 s.c.f.to about 75 s.c.f. per pound of carbon in the solid.

The process of the present invention may be employed in a batch typeoperation or a continuous type operation. When a batch operation isemployed, fixed amounts of the carbonaceous solid, water, the catalyticsulfur-conraining compound and the reducing gas are charged to asuitable liquefaction reactor, such as a rocking autoclave. Thereactants are contacted in the liquefaction reactor for a period of timesufficient to produce the desired amount of conversion and then theresulting mixture is withdrawn from the liquefaction zone and thedesired hydrocarbonaceous product is separated and recovered. A suitablecontact time in a batch type operation is about 1 minute to about 600minutes, preferably about 200 minutes to about 400 minutes. In acontinuous operation, the carbonaceous solid, water, thesulfur-containing compound and the reducing gas are continuously chargedto a suitable reaction zone and contacted therein. The resulting mixtureis continuously withdrawn from the reactor and the desiredhydrocarbonaceous product is separated and recovered. A suitable liquidhourly space velocity in a continuous type operation (volume of thereactor divided by the total volume of reactants charged per hour) ofabout 0.16 to about 1.0 may be employed, and about 0.25 to about 0.5 isparticularly preferred.

The liquefaction zone or reactor utilized in the present process may beany suitable vessel or reactor which can maintain the reactants atsufiicient temperature and pressure to provide the required liquefactionconditions. For example, a conventional rocking autoclave is a suitablereactor for use in a batch type operation. -A variety of vesselssuitable for use as the reactor are known in the art of coalliquefaction. Preferably, the liquefaction zone includes means foradmixing the reactants by stirring or other agitation.

The mixture recovered after the liquefaction step, in addition to thedesired hydrocarbonaceous product, will contain water, which is presentas a phase separate from the product. Most of the solids remaining inthe mixture: will be found in the water phase. Thus, thehydrocarbonaceous product may conveniently be separated from the: waterand from at least a major portion of any remaining: solid residualmaterials such as ash, by simple mechanical separation of the phasesprovided by settling the effluent from the liquefaction reactor. Thewater phase thus recovered may be recirculated to the reaction step forfurther use after purification, if desired. Similarly, reducing gaswhich is not consumed during the reaction, or liquefaction, step may berecovered and recirculated to the liquefaction step. I have found thatthe present process actually does not consume hydrogen or carbonmonoxide in substantial amounts, so that only a small amount ofcontinuously supplied fresh reducing gas is normally required in acontinuous operation. The hydrocarbonaceous product may be furtherprocessed, for example, by petroleum refining methods such as cracking,to provide hydrocarbon fuels, aromatic chemicals for petrochemical uses,etc. When the process herein disclosed is utilized to treat thepreferred carbonaceous solid, bituminous coal, the hydrocarbonaceousproduct recovered comprises a tarry material which is liquid at about100 C. and has an ash and sulfur content significantly lower than thatof the raw bituminous coal. One of the major problems encountered inprior art coal liquefaction processes has been the separation of ashfrom the hydrocarbonaceous materials produced. The present processreduces the amount of ash in the hydrocarbonaceous liquefaction productsufficiently that further separation of solids may not be necessary,particularly since much of the solid residue remains in the water phaseresulting from settling the liquefaction reactor efiluent and isconsequently very easily removed by decantation.

Liquefaction conditions may include the use of various catalysts tofurther enhance the liquefaction reactions in the present process.Suitable catalysts include metals from Group VIII of the Periodic Tableof The Elements, particularly the sulfides of these metals, especiallyiron sul fide, nickel sulfide and cobalt sulfide. The above-noted metalsulfide catalysts may be utilized at a concentration of about 0.001 wt.percent to about wt. percent of the amount of carbonaceous solidmaterial to be treated. A preferred concentration for such catalysts isabout 0.1 wt. percent to about 2 wt. percent of the carbonaceous solid.In general, a catalyst of this type may be employed by admixing it withthe pulverized coal as a solid.

The hydrocarbonaceous liquefaction product recovered from theliquefaction step is a tarry material melting at about 50 C. to about200 C., comprising a mixture of various hydrocarbonaceous compoundscontaining about 80-85 wt. percent carbon and about 6.58 wt. percenthydrogen. This liquefaction product is preferably further treated byconventional petroleum refining methods to provide hydrocarbon products.One particularly convenient method for recovering valuable components inthe liquefaction product and simultaneously removing any remaining ash,carbonaceous solids, etc., is by extracting the hydrocarbonaceousproduct with an organic solvent. The solvents which may be employed areWell known in the art. Examples of some suitable solvents which areparticularly preferred include benzene, toluene, xylene, and similar C Caromatics, hexane, heptane and similar C -C parafiins, ketones, C Ccycloparafiins and alkylcycloparafiins, etc. Extraction conditionsgenerally include a temperature of about 30 C. to about 300 C. andpreferably about 50 C. to about 150 C. Superatmospheric pressure isdesirable but not essential. After a con tact time of about 0.1 minuteto about 1500 minutes, the solvent and the extract materials dissolvedtherein are decanted or otherwise mechanically separated from whateversolid residual materfals remain at the extraction conditions employed.The extracted fraction is then recovered, e.g., by fractionation toseparate the solvent, or by other conventional methods.

The following examples illustrate various embodiments and advantages ofthe process of the present invention. The examples are not intended tolimit the broad scope of the present invention, and many otheradvantages and embodiments of the invention will be apparent to thoseskilled in the art from the description provided herein.

EXAMPLE I A seam coal from Randolph Co., Bellville District, Illinois,was analyzed to determine its average composition, which was found to beas shown in Table I.

6 TABLE I Wt. percent Ash 10.18 Total nitrogen 1.32 Leco sulfur 3.34Total oxygen 9.54 Free water 4.00

Volatiles 39.72 Carbon 64.45

Hydrogen 5.25 Dry ash 10.70

The coal was pulverized to provide particles sufficiently small to passthrough a 200 mesh Tyler screen. One hundred grams of the pulverizedcoal and 400 grams of water were placed in an 1850 cc. rockingautoclave. In this run, no sulfur-containing catalytic compounds wereemployed, in order to demonstrate the low yield obtained without theiruse. The autoclave was sealed and sufficient hydrogen was introduced toprovide a pressure of 70 atmospheres. The contents of the autoclave wereheated to a temperature of 350 C. and a pressure of 3.0 atmospheres inthe autoclave was observed. The contents were agitated at 350 C. for 6hours, and then the autoclave was cooled to room temperature. Thepressure was observed to 62 atmospheres. The excess pressure wasreleased and the remaining contents of the autoclave were removed. Theeflluent from the autoclave was observed to consist of a water phase anda hydrocarbonaceous phase. The hydrocarbonaceous phase, which solidifiedat about 100 C., was separated from the water phase by simpledecantation and dried. The hydrocarbonaceous materials were thenextracted with benzene at about -85 C. It was found that the benzenesoluble fraction of the hydrocarbonaceous phase contained 30 wt. percentof the carbon in the original grams of coal charged to the autoclave.

EXAMPLE II One hundred grams of the same pulverized coal employed inExample I was placed in the same autoclave used in Example I. No waterand no sulfur-containing catalytic compounds were employed in this run,in order to show the low yield obtained, even when using ahydrocarbonaceous solvent in the liquefaction operation. One hundred cc.of xylene was placed in the autoclave with the coal and the autoclavewas sealed. Sufiicient hydrogen was charged to the autoclave to producea pressure of 70 atmospheres. The contents of the autoclave wereagitated at a temperature of 350 C. for six hours. The contents werethen cooled and the excess pressure was released. After evaporation ofthe xylene solvent from the hydrocarbonaceous product and drying, theproduct was extracted with benzene in a manner identical to that used inExample I. It was found that 31 wt. percent of the carbon in theoriginal 100 grams charged to the autoclave had been converted tobenzene soluble hydrocarbons.

EXAMPLE III In this run, 100 grams of the pulverized coal described inExample I was placed in the same 1850 cc. autoclave with 300 cc. ofwater, 100 grams of (NI-10 5 0 and 7 grams of NH SH. The autoclave wassealed and pressured to 70 atmospheres with hydrogen. The contents ofthe autoclave were heated to 350 C., and a pressure of 350 atmosphereswas observed. The mixture in the autoclave was agitated at thattemperature for 6 hours and then cooled to room temperature. Excesspressure was released and the mixture was removed from the autoclave. Awater phase and suspended solids were separated and removed bydecantation. The hydrocarbonaceous product phase was dried at 100 C. andanalyzed. The hydrocarbonaceous product phase was then extracted withbenzene in a manner identical to that used in Examples I and II. It wasfound to contain 84 wt. percent carbon, 7 wt. percent hydrogen, 3.2 wt.percent oxygen and 3.4 wt. percent 7 sulfur, with 2.4 wt. percent ashand other materials. It was found that 61 wt. percent of the carbon inthe coal originally charged to the autoclave was contained in thebenzene soluble fraction of the hydrocarbonaceous product.

By comparing the results of Example III with those of Examples I and II,it is apparent that the process of the present invention provided asuprisingly greater amount of conversion. Where no sulfur-containingsalt was used in the liquefaction step, only 30% conversion wasobtained, and where a hydrocarbon solvent, but no water and nosulfur-containing compounds were used (Example II), only 31 wt. percentconversion was obtained. By employing the process of the presentinvention, in Example III, 61% conversion was obtained at identicalliquefaction conditions and product recovery conditions. Thus, thepresent process resulted in an increased conversion of substantially100% over that obtained without using the catalytic sulfur-containingsalt and also over that obtained using a hydrocarbon solvent.

EXAMPLE IV In this run, 100 grams of the pulverized coal described inExample I was charged to the same 1850 cc. autoclave. Also charged were400 cc. water, 100 grams Na S O and 7 grams NH SH. The autoclave wassealed, and sufiicient hydrogen was charged to provide a pressure of 70atmospheres. The mixture in the autoclave was agitated at 350 C. for 6hours and then cooled to room temperature. Excess pressure was releasedand the remaining contents were removed. The water and thehydrocarbonaceous product formed two separate phases, which wereseparated by decantation. The hydrocarbonaceous phase was dried andextracted with benzene in a manner identical to that used in theprevious examples. It was found that 52 wt. percent of the carbon in theoriginal 100 grams of coal was present in the benzene soluble fraction.Thus the method of the present invention provided a more than 70%greater conversion than the methods used in Examples I and II.

EXAMPLE V In order to demonstrate the necessity of employing a reducinggas in the liquefaction step, a run was undertaken without using areducing gas. In this run, 100 grams of coal, 400 cc. water, 100 gramsof Na S O and 7 grams of NH SH were placed in the same 1850 cc.autoclave as utilized in the previous examples. The autoclave wassealed, and sufficient nitrogen was charged to provide a pressure of 70atmospheres. The mixture in the autoclave was agitated at 350 C. for 6hours. The autoclave was then cooled to room temperature and the excesspressure was released. The mixture was removed from the autoclave andthe resulting water phase was separated by decantation. The remainingmaterials were dried at 100 C. and extracted with benzene in a manneridentical to that employed in the foregoing examples. It was found thatessentially none of the coal had been converted to materials which couldbe extracted with benzene.

EXAMPLE VI In this run, 100 grams of the puverized coal described inExample I, 400 cc. water, 100 grams of Na S O and 100 cc. xylene wereplaced in the 1850 cc. autoclave. The autoclave was sealed andsufiicient hydrogen was charged to increase the pressure to 70atmospheres. The mixture was agitated at 350 C. for 6 hours and thencooled to room temperature. The excess pressure was released and theremaining contents were removed from the autoclave. The water wasremoved by decantation and the hydrocarbonaceous product was dried at100 C. and extracted with benzene in the same procedure as employed inthe foregoing examples. The xylene solvent was removed by evaporationduring this drying operation. It was found that the benzene extractedhydrocarbons contained 65 wt.

percent of the carbon in the original coal charged to the autoclave.

EXAMPLE VII In this run, grams of the pulverized coal 0f Example I wasplaced in the 1,850 cc. autoclave with 300 cc. water, 100 grams of NaHS0 and 100 cc. xylene. The autoclave was sealed and pressurized to 70atmospheres with hydrogen. The contents of the autoclave were thenagitated at 350 C. for 6 hours. The mixture in the autoclave wasreturned to room temperature and excess pressure released. The remainingcontents were removed and the water was separated by decantation. Thehydrocarbonaceous produce was dried and extracted with benzene in theidentical procedure employed in the foregoing examples. It was foundthat 73 wt. percent of the carbon in the original coal charged to theautoclave was recovered in the benzene soluble hydrocarbons.

EXAMPLE VIII In this run, 100 grams of the coal described in Example I,100 cc. water, 100 grams Na s and 100 cc. xylene were charged to the1,850 cc. autoclave. The autoclave was sealed and pressured to 50atmospheres with hydrogen. The autoclave contents were heated to 350 C.and a pressure of 205 atmospheres was observed. The mixture in theautoclave was agitated at that temperature for 6 hours and then cooledto room temperature, and excess pressure was released. The mixture wasremoved and the water was separated by decantation. The xylene solventwas removed and the hydrocarbonaceous product dried at 100 C. The driedhydrocarbonaceous materials were extracted with benzene, the drying andextraction procedures being identical to those used in the foregoingexamples. It was found that 57 Wt. percent of the carbon in the original100 gram charge was recovered in the benzene soluble extract fraction.

EXAMPLE IX In this run, 100 grams of the pulverized coal of Example Iwas placed in the 1,850 cc. autoclave with 100 cc. water, 50 grams Na SO50 grams NaHSO and 100 cc. xylene. The autoclave was sealed andsufiicient hydrogen was introduced to provide 50 atmospheres pressure.The mixture in the autoclave was agitated at 350 C. for 6 hours and thencooled to room temperature. Excess pressure was released and theremaining contents were removed. After decantation of the water, dryingand extraction of the hydrocarbonaceous products in a manner identicalto that used in the previous examples, it was found that the benzeneextracted fraction contained 53 wt percent of the carbon originallycharged in the coal.

EXAMPLE X In this run, 100 grams of the coal of Example I was charged tothe 1,850 cc. autoclave with 100 cc. water, 50 grams NaH S0 50 grams Nas and 100 cc. xylene. The autoclave was sealed and sufficient hydrogenwas charged to provide a pressure of 50 atmospheres. After the mixturewas agitated at 350 C. for 6 hours, it was cooled to room temperatureand excess pressure was released. The remaining contents were removedfrom the autoclave and the water was separated by decantation. Afterdrying and extracting the hydrocarbonaceous product with benzene, it wasfound that the benzene extracted fraction of the product contained 53wt. percent of the carbon in the original charge to the autoclave.

The foregoing clearly demonstrates the superior conversion achievedusing the processing conditions and components of the present invention,and indicates a preferred mode of operation of the present process whena batch reaction scheme is employed. Modification of the operation to acontinuous type operation, etc., will be obvious to those skilled in theart.

I claim as my invention:

1. A process for the liquefaction of coal which comprises contacting thecoal, at a temperature of from about 150 C. to about 375 C. and apressure of from about 10 to about 300 atmospheres for a contact timecorresponding to from 1 to 600 minutes or a liquid hourly spacedvelocity of about 0.16 to about 1.0, with from about 100 wt. percent toabout 1,000 wt. percent of water, a reducing gas selected from the groupconsisting of hydrogen, carbon monoxide and mixtures thereof in anamount of from about 0.5 to about 175 scf. per pound of carbon in thecoal, and from about 0.01 wt. percent to about 1,000 wt. percent of acatalyst consisting essentially of a catalytic sulfur compound selectedfrom the group consisting of alkali metal and ammonium sulfides,sulfites and thiosulfates.

2. The process of Claim 1 wherein said catalytic compound is an alkalimetal sulfide.

3. The process of Claim 1 where said catalytic compound is an alkalimetal sulfite.

4. The process of Claim 1 wherein said catalytic compound is an alkalimetal thiosulfate.

5. The process of Claim 1 wherein said alkali metal is selected fromsodium and potassium.

6. The process of Claim 1 wherein said catalytic compound is selectedfrom ammonium sulfide, ammonium sulfite and ammonium thiosulfate.

7. The process of Claim 1 wherein said reducing gas comprises hydrogen.

8. The process of Claim 1 wherein said reducing gas comprises carbonmonoxide.

9. The process of Claim 1 wherein at least a portion of said water is inthe liquid phase, and the liquefaction con- 10 ditions include atemperature of about 200 C. to about 375 C. and a pressure sufficient tomaintain at least a portion of said water in the liquid phase.

10. The process of Claim 1 wherein the reaction mixture is separatedinto an aqueous phase and a hydrocarbonaceous phase, and liquidhydrocarbon product is recovered from the hydrocarbonaceous phase.

11. The process of Claim 10 wherein said hydrocarbonaceous phase isextracted with an aromatic or paraffinic hydrocarbon solvent to providean extract fraction and an insoluble fraction, and said product isrecovered from the extract fraction.

12. The process of Claim 1 wherein said solvent is a monocyclic aromatichydrocarbon.

13. The process of Claim 1 wherein said coal is also contacted withabout 1.0 wt. percent to about 1,000 wt. percent of a hydrocarbonsolvent selected from benzene, toluene, xylene and ethylbenzene.

References Cited UNITED STATES PATENTS 1,959,175 5/1934 Pier et a1.208-10 3,642,607 2/ 1972 Seitzer 20810 3,687,838 8/1972 Seitzer 208-101,852,988 4/1932 Varga 20810 1,894,926 l/ 1933 Varga 208-10 2,123,6237/1938 Brown 208-10 2,039,259 4/ 1936 Pier ct a1 208-l0 VERONICA OKEEFE,Primary Examiner

1. A PROCESS FOR THE LIQUEFACTION OF COAL WHICH COMPRISES CONTACTING THE COAL, AT A TEMPERATURE OF FROM ABOUT 150:C TO ABOUT 375*C AND A PRESSURE OF FROM ABOUT 10 TO ABOUT 300 ATMOSPHERES FOR A CONTACT TIME CORRESPONDING TO FORM 1 TO 600 MINUTES OR A LIQUID HOURLY SPACED VELOCITY OF ABOUT 0.16 TO ABOUT 1.0, WITH FROM ABOUT 100 WT. PERCENT TO ABOUT 1,000 WT. PERCENT OF WATER, A REDUCTING GAS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN CARBON MONOXIDE AND MIXTURES THEREOF IN AN AMOUNT OF FROM ABOUT 0.5 TO ABOUT 175 SCF. PER POUND OF CARBON IN THE COAL, AND FROM ABOUT 0.01 WT. PERCENT TO ABOUT 1,000 WT. PERCENT OF A CATALYST CONSISTING ESSENTIALLY OF A CATALYTIC SULFUR COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL AND AMMONIUM SULFIDES, SULFITES AND THIOSULFATES. 